1. Field of the Invention
The present invention relates to a data processing technology and, more particularly, to a technology for viewing restriction of electronic data.
2. Description of the Related Art
Email is a widely technology for transmitting information among a plurality of users. However, problems can occur due to erroneous transmission of email.
The following Patent Document No. 1 suggests a communication system that suppresses the opening of the text of a transmitted email at the destination of said transmitted email. More specifically, a relay apparatus that relays email is provided in the system, and the relay apparatus stores the text of the email in memory and allows receipt of the text of the email when a destination terminal requests to view the email. Further, the relay apparatus deletes the text of the email in the memory of the relay apparatus when such action is requested by a terminal.
[Patent Document No. 1] Japanese Patent Application Publication NO. 2011-10093
In the above Patent Document No. 1, it is necessary to store and accumulate the data of an already-transmitted email in a server (for example, a relay apparatus according to Patent Document No. 1) located within the jurisdiction of a transmitter organization from which the email is sent. In the technology according to Patent Document No. 1, an increase in the required amount of system resources of a server is expected when, for example, a large amount of email data is stored. The inventors of the present invention consider that there is room for improvement in order to efficiently restrict the receipt of an already-transmitted email to a destination terminal.